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Main
Date: 27 Jun 2007 09:09:17
From: Margo Schulter
Subject: Advice on use of straight finder?
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Hello, everyone, and I'm seeking advice on the ergonomics of how
to use a 9X50 straight finder with a minimum of neck strain. This
finder, which looks quite nice, is on my new Sky-Watcher 20cm f/6
Dobsonian, which I hope will be seeing its first light within the
next week or so.
While a friend very favorably impressed with the construction of
the scope advised me that I might consider a right-angle finder
or red dot finder (the Telrad looks like a good choice for the
latter approach), making the most of the straight-through 9X50
finder very much appeals to me. This finder seems, so to speak,
a not too distant cousin to the 7X50 binoculars I use with
Taki's 8.5 Magnitude Star Atlas, often in light-polluted urban
conditions with a limiting magnitude around 3, for starhopping
by asterisms not readily visible to the naked eye. At my age,
maybe the smaller exit pupil of the 9X50 finder might help <grin >.
Would people have advice as to minimizing strain with this type
of finder? Here are some possible questions which occur to me as
someone focusing mainly on deep-sky observing:
(1) Might it be a good rule to avoid or minimize
use of the finder at or very close to the zenith?
An alternative might be to use as a kind of finder
my widest-field EP, a 30mm "not-quite-Nagler" with
a tad more than 2deg TFOV at 40X. Maybe some
extra study of an atlas for areas of interest that
are going to be near the zenith during a given
observation could make this strategy more successful.
(2) Might a good adjustable observing chair help with
finder ergonomics, as well as with other aspects
of observing like being more relaxed and thus
able better to concentrate on those elusive
faint fuzzies?
Maybe people's experience might reveal other aspects of the
question that haven't occurred to me; thank you in advance
for any suggestions.
Most appreciatively,
Margo Schulter
mschulter@calweb.com
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Date: 06 Jul 2007 01:03:44
From: Stuart Levy
Subject: Re: Advice on use of straight finder?
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On 2007-06-27, Margo Schulter <mschulter@web1.calweb.com > wrote:
> Hello, everyone, and I'm seeking advice on the ergonomics of how
> to use a 9X50 straight finder with a minimum of neck strain. This
> finder, which looks quite nice, is on my new Sky-Watcher 20cm f/6
> Dobsonian, which I hope will be seeing its first light within the
> next week or so.
>
> While a friend very favorably impressed with the construction of
> the scope advised me that I might consider a right-angle finder
> or red dot finder (the Telrad looks like a good choice for the
> latter approach), making the most of the straight-through 9X50
> finder very much appeals to me. This finder seems, so to speak,
> a not too distant cousin to the 7X50 binoculars I use with
> Taki's 8.5 Magnitude Star Atlas, often in light-polluted urban
> conditions with a limiting magnitude around 3, for starhopping
> by asterisms not readily visible to the naked eye. At my age,
> maybe the smaller exit pupil of the 9X50 finder might help <grin>.
Glad you're doing this -- I love straight-through magnifying finders.
As monocular devices, you won't see nearly as well through them
as through a comparable pair of binoculars, but they're still
extremely helpful, especially if your skies aren't very dark.
I observe mostly from the city, where a Telrad pointed almost anywhere
just shows blank sky, but a magnifying finder generally shows something.
I have a 6" f/8 Dob, so comparable f.l. to yours.
One thing that really helps me is kneeling. A deep pad of soft foam
makes it much more comfortable, and keeps knees warm clean and dry.
If you can stand to do that at all, it's liable to put your head in
a much more stable, relaxed viewing position than you'd have if
stooping and trying to crane your neck, especially when looking
high in the sky. The only disadvantage is that you often have to
switch between kneeling (finder view) and standing (eyepiece view).
If you have an outdoor cat, you may find the cat lounging on your
calves for warmth in cool weather; this could be considered a feature.
If choosing a new finder, I'd probably have picked one with
a bit less magnification than 9x -- maybe 7x -- to make it easier
to coordinate the unaided-eye's view with the magnified view. But
I'm sure you'll get used to it.
I've never found an observing chair that helped me much,
but will be interested to hear what others say about them.
cheers
Stuart Levy in steamy (but clear!) Champaign, IL
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Date: 06 Jul 2007 06:37:00
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
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Stuart Levy <s_levy@ameritech.net > wrote:
> Glad you're doing this -- I love straight-through magnifying finders.
> As monocular devices, you won't see nearly as well through them
> as through a comparable pair of binoculars, but they're still
> extremely helpful, especially if your skies aren't very dark.
> I observe mostly from the city, where a Telrad pointed almost anywhere
> just shows blank sky, but a magnifying finder generally shows something.
> I have a 6" f/8 Dob, so comparable f.l. to yours.
Thank you for this helpful feedback. Around my apartment, I'm evidently
dealing with a limiting magnitude somewhere around 3.2-3.5, I might guess,
based on letting my eyes get a bit dark-adapted and then comparing what
I can see in the region around Antares or that of the handle of the
"tea kettle" in Sagittarius to the magnitudes shown on a star chart.
Binocular asterisms are, of course, invaluable in finding something like
M7 or M8, and I hope that the finder is simlarly helpful.
One note on a complication of using the finder that I haven't seen
mentioned anywhere, either because it's so routine as a beginner
initiation that it might not get mentioned, or because it might
reflect my own depth perception problems rather than the experience
of a typical user.
I had a not-very-successful first try at using the telescope under
very much less than ideal circumstances, but did manage to use the finder.
The unexpected complication was that when I tried to view not too far
from the zenith, I found that it was easy to miss the intended position
for my eye and have the finder nudge or bump me in the area above the eye.
It's the kind of thing I might want to put other newbies on notice about --
or at least those sharing my depth perception problem, which maybe isn't
so common a situation.
> One thing that really helps me is kneeling. A deep pad of soft foam
> makes it much more comfortable, and keeps knees warm clean and dry.
> If you can stand to do that at all, it's liable to put your head in
> a much more stable, relaxed viewing position than you'd have if
> stooping and trying to crane your neck, especially when looking
> high in the sky. The only disadvantage is that you often have to
> switch between kneeling (finder view) and standing (eyepiece view).
> If you have an outdoor cat, you may find the cat lounging on your
> calves for warmth in cool weather; this could be considered a feature.
That sounds like a neat technique, and maybe also a reason to seek out
other amateur astronomers (or friends who might be interested) who have
cats and would like to join in an observing session.
> If choosing a new finder, I'd probably have picked one with
> a bit less magnification than 9x -- maybe 7x -- to make it easier
> to coordinate the unaided-eye's view with the magnified view. But
> I'm sure you'll get used to it.
That's an interesting point. By the way, while the finder is 9x50
according to the specs on the Web, I noticed that the box has a
notation including "8x" -- although that possibly could be some
code other than the magnification. The notation is:
BZX-01-P10-02
(8x)
> I've never found an observing chair that helped me much,
> but will be interested to hear what others say about them.
>
> cheers
>
> Stuart Levy in steamy (but clear!) Champaign, IL
Thanks for the advice -- and encouragement. Here in Sacramento, CA
it's quite hot, so that a cooling summer breeze is very welcome
if and when it comes in, but not necessarily for its effect on
seeing <grin >.
With many thanks,
Margo
mschulter@calweb.com
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Date: 30 Jun 2007 02:33:25
From:
Subject: Re: Advice on use of straight finder?
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On Jun 29, 4:37 am, Margo Schulter <mschul...@web1.calweb.com > wrote:
> The two have LightBridge 12" f/5 Dobs,
> a nice pair on which they can try and demonstrate different eyepieces.
> For observations while standing, this scope nicely matched my height.
Yes, I own a 12.5" f/5, and it's great for observing stuff high in the
sky. But point it 30 degrees above the horizon, and you're back in the
same old pickle. The beauty of my 7" f/5.6 is that it's comfortable
while sitting in a standard chair at *all* telescope angles. But
that's only possible because its tube is quite short.
> So far, I've been using _Taki's 8.5 Magnitude Star Atlas_, which seems
> very nice and reasonably comprehensive; but I'd suspect that a bit of
> experience starhopping with a 2-degree field should show how adequate
> or otherwise it is for this purpose.
Yes, mag 8.5 is adequate for star-hopping through a 2-degree field --
though barely.
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Date: 01 Jul 2007 23:20:38
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
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tony_flanders@yahoo.com wrote:
> On Jun 29, 4:37 am, Margo Schulter <mschul...@web1.calweb.com> wrote:
>> The two have LightBridge 12" f/5 Dobs,
>> a nice pair on which they can try and demonstrate different eyepieces.
>> For observations while standing, this scope nicely matched my height.
>
> Yes, I own a 12.5" f/5, and it's great for observing stuff high in the
> sky. But point it 30 degrees above the horizon, and you're back in the
> same old pickle. The beauty of my 7" f/5.6 is that it's comfortable
> while sitting in a standard chair at *all* telescope angles. But
> that's only possible because its tube is quite short.
Hi, Tony. That observation about objects near the horizon with an f/5 Dob
around 12-12.5" fits with what happened toward the end of the session with
my two friends. With my binoculars, I spotted a DSO that I guessed might be
M7 (or possibly also M6, it was suggested) -- but when it was located with
one of those Dobs using a green laser pointer, the ergonomics didn't make
it such a tempting observing situation with that instrument.
Thus your 7" f/5.6 scope does sound like a neat design!
>> So far, I've been using _Taki's 8.5 Magnitude Star Atlas_, which seems
>> very nice and reasonably comprehensive; but I'd suspect that a bit of
>> experience starhopping with a 2-degree field should show how adequate
>> or otherwise it is for this purpose.
>
> Yes, mag 8.5 is adequate for star-hopping through a 2-degree field --
> though barely.
Thanks for this feedback based on experience I'm looking to get. Of course,
I realize that for really ambitious objects for a 20cm reflector, for
example NGC 224/M31-G1 (globular cluster G1 of M31, reportedly the largest
known globular in our Local Group of galaxies), I'm going need either a
superb atlas or object-specific finder charts -- as well as a really dark
site, thoroughly dark-adapted eyes, and the skill and experience needed to
make the most of these.
Most appreciatively,
Margo
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Date: 29 Jun 2007 08:59:01
From: Gil
Subject: Re: Advice on use of straight finder?
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On Jun 29, 4:37 am, Margo Schulter <mschul...@web1.calweb.com > wrote:
> Thanks to everyone for your informative and encouraging replies. I can
> readily see that on the utility and comfort of the straight finder,
> people's experiences and opinions are diverse -- and that I'll need to
> find out for myself, but going into the process better informed by
> your suggestions.
>
> I'm still catching up with your most generous responses here, and these
> are some first impressions on a few points raises.
>
> [Unk Rod]
>
> > I suspect with a little practice you'll find the straight through
> > finder is not as much of a problem to use as you think. A right-angle-
> > correct-image finder is an option, but I find these actually _more_
> > awkward to use.
>
> Hi, Rod. Maybe I should clarify that the idea that the finder might be
> a "problem" came from a friend who helped me set up the scope. My own
> inclination is to learn to use it and enjoy it. Your encouragement in
> this direction is most welcome.
>
> While the main factor leaning me in favor of the straight-through
> finder is a desire to make the most of what looks like very nice and
> substantial component for the scope, there's also the appeal of
> learning to use an observing tool with a long historical tradition.
> I'm the kind of person who asks to what size of metal speculum mirror
> a modern 20cm glass mirror might be equivalent -- an imprecise
> question, of course, for a number of reasons, not the least of which
> is the varying quality of mirrors both in the Herschelian era and now.
>
> [Bud]
>
> > A adjustable chair increases the comfort factor.
>
> Yes, and what I've read about DSO observing, as well as my experience
> so far in an otherwise maybe not-so-ideal bright-sky location where I
> can use binoculars from a comfortable seated position, suggest to me
> that I definitely want one.
>
> [Tony Flanders]
>
> > Those 200mm f/6 Dobs do tend to put both the eyepiece and the finder
> > at a very awkward height -- to low to view comfortably while
> > standing but too high to view from a standard chair. I've never
> > owned one, but a tall adjustable-height chair seems like the obvious
> > solution. Unfortunately, they're necessarily pretty heavy and
> > bulky.
>
> Yes, I learned "where I stood" on the Dob height scale on a recent
> trip with a couple of friends and my accustomed 7X50 binoculars to a
> fairly dark-sky site in the Sierra foothills of northern central
> California called Cronan Ranch. The two have LightBridge 12" f/5 Dobs,
> a nice pair on which they can try and demonstrate different eyepieces.
> For observations while standing, this scope nicely matched my height.
> My main concern about sharing this story is that it might provide
> people with yet another excuse for aperture fever <grin>.
>
> The good news may be that when I look at the zenith eyepiece height of
> my 200mm f/6 Dob while sitting in what seems to be a fairly average
> standard chair, it comes to about the top of my head -- so that an
> adjustable chair might not have to rise too high, at least to
> accommodate me. For a setting like a star party, of course, a wide
> range of adjustability wouldn't hurt.
>
> By the way, I have a friend of more moderate stature for whom my Dob
> might be a reasonable fit -- she may be present at the scope's first
> light.
>
> [Ernie]
>
> > I built a box to put my 8-inch f/6 Dob on. It's about 15 inches
> > high, made of pressure-treated 2x4s and some lag bolts. It's not
> > attached to the base, so it's always optional and has no effect on
> > portability. I use it as the base of a side table on my deck when
> > it's not under the Dob.
>
> That's a neat solution, if I could find a craftsperson who could
> reliably replicate the stability of your design -- I could use the box
> for more "casual" styles of observing while standing, say, and an
> adjustable chair for maximum comfort and concentration. While the
> chair is my first priority now, that wouldn't exclude your option
> also.
>
> [Tony]
>
> > It's very useful to be able to star-hop through your eyepiece as
> > well as through your finderscope. It *does* require excellent star
> > charts -- but sooner or later, you're going to need those anyway.
>
> So far, I've been using _Taki's 8.5 Magnitude Star Atlas_, which seems
> very nice and reasonably comprehensive; but I'd suspect that a bit of
> experience starhopping with a 2-degree field should show how adequate
> or otherwise it is for this purpose. In the meantime, I get your hint
> that it's a bit different than binocular starhopping with a 7.1-degree
> field!
>
> [wsnell01]
>
> > What works for me is to use a somewhat larger finder that has a
> > higher mag and is equipped with a wide-field eyepiece. This lets me
> > get the scope pointed at a star field very quickly because I can
> > easily see the stars and asterisms shown on my chart and sometimes
> > the target object itself.
>
> What I'm picturing is maybe something like a 60mm refractor with an
> eyepiece having an AFOV around 72 degrees and a magnification around
> 18X, say, for a field of about 4 degrees. That might be comparable to
> some of the basic scopes of the 17th and 18th centuries used to make
> lots of deep-sky discoveries -- which would fit with your ability
> sometimes to see "the target object itself." I'd love to learn more
> about your setup; while this might be a bit of ambitious solution for
> me, I've seen it recommended as ideal.
>
> With many thanks,
>
> Margo Schulter
> mschul...@calweb.com
Right-angle finders are a colossal pain. With the f/6 scope, you will
be in the ballpark quite easily with a straight finder, but you do
have to "crane your neck" a bit!
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Date: 01 Jul 2007 23:42:07
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
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Gil <gilbertviolette@sbcglobal.net > wrote:
> Right-angle finders are a colossal pain. With the f/6 scope, you will
> be in the ballpark quite easily with a straight finder, but you do
> have to "crane your neck" a bit!
Hi, Gil.
Maybe one of my questions would be whether there are any tricks or
techniques for minimizing any neck strain when doing the inevitable
"craning" -- the way I move my neck to approach the finder, for
example, or the amount of time I look before getting back to a more
relaxed position for a while?
Most appreciatively,
Margo
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Date: 29 Jun 2007 04:50:49
From: Arktouross
Subject: Re: Advice on use of straight finder?
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On Jun 27, 3:09 am, Margo Schulter <mschul...@web1.calweb.com > wrote:
> Hello, everyone, and I'm seeking advice on the ergonomics of how
> to use a 9X50 straight finder with a minimum of neck strain.
Ditch the finder completely and only use a telrad.
Nick
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Date: 29 Jun 2007 06:20:24
From: Curtis Croulet
Subject: Re: Advice on use of straight finder?
|
>> Hello, everyone, and I'm seeking advice on the ergonomics of how
>> to use a 9X50 straight finder with a minimum of neck strain.
>
> Ditch the finder completely and only use a telrad.
A Telrad is fine for pointing the scope to M13 and M42. For star-hopping to
fainter stuff, you need an optical finder. However, one function of a
finder is simply to get the scope pointed in the general direction (after
which you zero in on what you want), and, for that, a Telrad is helpful even
if an optical finder is available. However, the best 1x finder I've used is
the Tele Vue Starbeam on my TV-85. A straight-thru finder is easy to use in
any position on my Newtonians, but I concede that a straight-thru is mighty
uncomfortable with my SCT pointed near the zenith.
--
Curtis Croulet
Temecula, California
33°27'59"N, 117°05'53"W
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Date: 30 Jun 2007 05:35:49
From: David Knisely
Subject: Re: Advice on use of straight finder?
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Curtis Croulet posted:
> A Telrad is fine for pointing the scope to M13 and M42. For star-hopping to
> fainter stuff, you need an optical finder. However, one function of a
> finder is simply to get the scope pointed in the general direction (after
> which you zero in on what you want), and, for that, a Telrad is helpful even
> if an optical finder is available. However, the best 1x finder I've used is
> the Tele Vue Starbeam on my TV-85. A straight-thru finder is easy to use in
> any position on my Newtonians, but I concede that a straight-thru is mighty
> uncomfortable with my SCT pointed near the zenith.
Well, maybe not. A friend of mine used only a Telrad on his 20 inch
Obsession and was finding things I had trouble finding even with my
optical finderscope. That was what convinced me to put one on my 10
inch. Now, if I want to find the Markarian Chain, I just put the center
of the Telrad halfway between Denebola and Vindemaitrix and *boom*, I am
right there without having to even look in the finderscope. The three
rings (0.5 degrees, 2 degrees, and 4 degrees in diameter on the sky),
and are most useful, not just as a simple bulls-eye, but as a "pattern
maker", for star hopping. By using overlays which resemble the Telrad's
reticle pattern on star atlases, and centering the target object's chart
location in the overlay, star patterns and alignments with the Telrad
rings in the area around deep-sky objects can be worked out which can
then be duplicated by looking through the Telrad at the night sky. The
Telrad rings can also be used as measured "steps" in extended star hops.
This can make finding even faint non-naked eye objects much easier
than with the simple "dot" finders. Those people who insist on
downplaying the Telrad's usefulness based on merely using the unit only
as a "bull's-eye" centering finder like the "dot" sights do not really
understand how to use a Telrad! It is the pattern making or
stepping-off field size which makes it a truly valuable finding device
for the telescope. Clear skies to you.
--
David W. Knisely KA0CZC@navix.net
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/
**********************************************
* Attend the 14th Annual NEBRASKA STAR PARTY *
* July 15th-20th, 2007, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************
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Date: 02 Jul 2007 00:23:42
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
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David Knisely <KA0CZC@navix.net > wrote:
> Curtis Croulet posted:
>
>> A Telrad is fine for pointing the scope to M13 and M42. For star-hopping to
>> fainter stuff, you need an optical finder. However, one function of a
>> finder is simply to get the scope pointed in the general direction (after
>> which you zero in on what you want), and, for that, a Telrad is helpful even
>> if an optical finder is available. However, the best 1x finder I've used is
>> the Tele Vue Starbeam on my TV-85. A straight-thru finder is easy to use in
>> any position on my Newtonians, but I concede that a straight-thru is mighty
>> uncomfortable with my SCT pointed near the zenith.
Hi, Curtis and David.
One quick point I might add is that some kind of optical finder, I might guess
from my urban experiences with binoculars, is especially important in heavily
light-polluted skies where there are not a lot of naked-eye stars available
for navigating with 1x finders -- as useful as they are in darker skies. Often
I find myself, in an urban setting, navigating maybe by jumping off from Antares
and proceeding mainly by binocular asterisms to M7 or M8 or the like.
By the way, Curtis, I take note of your experience, like that of some others
here, that a straight-through finder can be quite satisfactory on a Dob or other
Newt -- something that lends encouragement as I look forward to learning this art.
> Well, maybe not. A friend of mine used only a Telrad on his 20 inch
> Obsession and was finding things I had trouble finding even with my
> optical finderscope. That was what convinced me to put one on my 10
> inch. Now, if I want to find the Markarian Chain, I just put the center
> of the Telrad halfway between Denebola and Vindemaitrix and *boom*, I am
> right there without having to even look in the finderscope. The three
> rings (0.5 degrees, 2 degrees, and 4 degrees in diameter on the sky),
> and are most useful, not just as a simple bulls-eye, but as a "pattern
> maker", for star hopping. By using overlays which resemble the Telrad's
> reticle pattern on star atlases, and centering the target object's chart
> location in the overlay, star patterns and alignments with the Telrad
> rings in the area around deep-sky objects can be worked out which can
> then be duplicated by looking through the Telrad at the night sky.
David, looking at a few examples of Telrad charts on the Web nicely
illustrated these points for me -- at least as best as they can be
illustrated short of getting out there with a Telrad and using it.
I was almost tempted to imagine certain "purists" debating whether
a Telrad was so powerful that it might give an inordinate advantage
in a Messier Marathon, for example. Anyway, I quickly got the idea
that a Telrad isn't just a pointing device: it's a _measuring_ device.
> The Telrad rings can also be used as measured "steps" in extended star hops.
> This can make finding even faint non-naked eye objects much easier
> than with the simple "dot" finders. Those people who insist on
> downplaying the Telrad's usefulness based on merely using the unit only
> as a "bull's-eye" centering finder like the "dot" sights do not really
> understand how to use a Telrad! It is the pattern making or
> stepping-off field size which makes it a truly valuable finding device
> for the telescope. Clear skies to you.
Recalling Tony's comment about how starhopping with a 2-degree eyepiece
field is a _lot_ slower than with 5-7 degree field (as in a usual finder
or binoculars), I wonder how fast it could go with a 2-degree eyepiece
plus a Telrad.
Most appreciatively,
Margo
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Date: 29 Jun 2007 08:37:13
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
|
Thanks to everyone for your informative and encouraging replies. I can
readily see that on the utility and comfort of the straight finder,
people's experiences and opinions are diverse -- and that I'll need to
find out for myself, but going into the process better informed by
your suggestions.
I'm still catching up with your most generous responses here, and these
are some first impressions on a few points raises.
[Unk Rod]
> I suspect with a little practice you'll find the straight through
> finder is not as much of a problem to use as you think. A right-angle-
> correct-image finder is an option, but I find these actually _more_
> awkward to use.
Hi, Rod. Maybe I should clarify that the idea that the finder might be
a "problem" came from a friend who helped me set up the scope. My own
inclination is to learn to use it and enjoy it. Your encouragement in
this direction is most welcome.
While the main factor leaning me in favor of the straight-through
finder is a desire to make the most of what looks like very nice and
substantial component for the scope, there's also the appeal of
learning to use an observing tool with a long historical tradition.
I'm the kind of person who asks to what size of metal speculum mirror
a modern 20cm glass mirror might be equivalent -- an imprecise
question, of course, for a number of reasons, not the least of which
is the varying quality of mirrors both in the Herschelian era and now.
[Bud]
> A adjustable chair increases the comfort factor.
Yes, and what I've read about DSO observing, as well as my experience
so far in an otherwise maybe not-so-ideal bright-sky location where I
can use binoculars from a comfortable seated position, suggest to me
that I definitely want one.
[Tony Flanders]
> Those 200mm f/6 Dobs do tend to put both the eyepiece and the finder
> at a very awkward height -- to low to view comfortably while
> standing but too high to view from a standard chair. I've never
> owned one, but a tall adjustable-height chair seems like the obvious
> solution. Unfortunately, they're necessarily pretty heavy and
> bulky.
Yes, I learned "where I stood" on the Dob height scale on a recent
trip with a couple of friends and my accustomed 7X50 binoculars to a
fairly dark-sky site in the Sierra foothills of northern central
California called Cronan Ranch. The two have LightBridge 12" f/5 Dobs,
a nice pair on which they can try and demonstrate different eyepieces.
For observations while standing, this scope nicely matched my height.
My main concern about sharing this story is that it might provide
people with yet another excuse for aperture fever <grin >.
The good news may be that when I look at the zenith eyepiece height of
my 200mm f/6 Dob while sitting in what seems to be a fairly average
standard chair, it comes to about the top of my head -- so that an
adjustable chair might not have to rise too high, at least to
accommodate me. For a setting like a star party, of course, a wide
range of adjustability wouldn't hurt.
By the way, I have a friend of more moderate stature for whom my Dob
might be a reasonable fit -- she may be present at the scope's first
light.
[Ernie]
> I built a box to put my 8-inch f/6 Dob on. It's about 15 inches
> high, made of pressure-treated 2x4s and some lag bolts. It's not
> attached to the base, so it's always optional and has no effect on
> portability. I use it as the base of a side table on my deck when
> it's not under the Dob.
That's a neat solution, if I could find a craftsperson who could
reliably replicate the stability of your design -- I could use the box
for more "casual" styles of observing while standing, say, and an
adjustable chair for maximum comfort and concentration. While the
chair is my first priority now, that wouldn't exclude your option
also.
[Tony]
> It's very useful to be able to star-hop through your eyepiece as
> well as through your finderscope. It *does* require excellent star
> charts -- but sooner or later, you're going to need those anyway.
So far, I've been using _Taki's 8.5 Magnitude Star Atlas_, which seems
very nice and reasonably comprehensive; but I'd suspect that a bit of
experience starhopping with a 2-degree field should show how adequate
or otherwise it is for this purpose. In the meantime, I get your hint
that it's a bit different than binocular starhopping with a 7.1-degree
field!
[wsnell01]
> What works for me is to use a somewhat larger finder that has a
> higher mag and is equipped with a wide-field eyepiece. This lets me
> get the scope pointed at a star field very quickly because I can
> easily see the stars and asterisms shown on my chart and sometimes
> the target object itself.
What I'm picturing is maybe something like a 60mm refractor with an
eyepiece having an AFOV around 72 degrees and a magnification around
18X, say, for a field of about 4 degrees. That might be comparable to
some of the basic scopes of the 17th and 18th centuries used to make
lots of deep-sky discoveries -- which would fit with your ability
sometimes to see "the target object itself." I'd love to learn more
about your setup; while this might be a bit of ambitious solution for
me, I've seen it recommended as ideal.
With many thanks,
Margo Schulter
mschulter@calweb.com
|
| | | | |
Date: 29 Jun 2007 17:30:46
From: John Nichols
Subject: Re: Advice on use of straight finder?
|
"Margo Schulter" <mschulter@web1.calweb.com > wrote in message
news:4684c4b9$0$22475$d368eab@news.calweb.com...
> Thanks to everyone for your informative and encouraging replies. I can
> readily see that on the utility and comfort of the straight finder,
> people's experiences and opinions are diverse -- and that I'll need to
> find out for myself, but going into the process better informed by
> your suggestions.
>
> I'm still catching up with your most generous responses here, and these
> are some first impressions on a few points raises.
>
<snip > >
>> A adjustable chair increases the comfort factor.
>
> Yes, and what I've read about DSO observing, as well as my experience
> so far in an otherwise maybe not-so-ideal bright-sky location where I
> can use binoculars from a comfortable seated position, suggest to me
> that I definitely want one.
>
Adjustable observing chairs are an absolute must. CosmoComfort
(www.cosmocomfort.com) makes a really good one. Among other things, both
the seat and back are padded. You can get it for under $200 at Oceanside
Pacific.
> [Tony Flanders]
>
>> Those 200mm f/6 Dobs do tend to put both the eyepiece and the finder
>> at a very awkward height -- to low to view comfortably while
>> standing but too high to view from a standard chair. I've never
>> owned one, but a tall adjustable-height chair seems like the obvious
>> solution. Unfortunately, they're necessarily pretty heavy and
>> bulky.
>
> Yes, I learned "where I stood" on the Dob height scale on a recent
> trip with a couple of friends and my accustomed 7X50 binoculars to a
> fairly dark-sky site in the Sierra foothills of northern central
> California called Cronan Ranch. The two have LightBridge 12" f/5 Dobs,
> a nice pair on which they can try and demonstrate different eyepieces.
> For observations while standing, this scope nicely matched my height.
> My main concern about sharing this story is that it might provide
> people with yet another excuse for aperture fever <grin>.
>
Aha, another tall person! I use a Telrad, and sometimes my 9x50 finder. I
can't say the Telrad is a problem, as I have it mounted near the front of
the OTA. The 9x50 frequently is literally a pain in the neck, as it's
closer to the opposite end of my OTA, and anything near the zenith is just
about impossible, even with my observing chair lowered completely.
Sometimes I have to sit on the ground, which is not optimal for someone with
back and knee issues, like me.
|
| | | | | |
Date: 02 Jul 2007 00:05:20
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
|
John Nichols <bejay@worldnet.att.net > wrote:
>
> Aha, another tall person! I use a Telrad, and sometimes my 9x50 finder. I
> can't say the Telrad is a problem, as I have it mounted near the front of
> the OTA. The 9x50 frequently is literally a pain in the neck, as it's
> closer to the opposite end of my OTA, and anything near the zenith is just
> about impossible, even with my observing chair lowered completely.
> Sometimes I have to sit on the ground, which is not optimal for someone with
> back and knee issues, like me.
Hi, John, and thanks for this perspective. On my Dob, the finder is mounted
near the focuser; this might alleviate the zenith problem a bit, more so from
a good observing chair -- although some neck craning is still obviously
required. As you say, sitting on the ground is a lot less than optimal!
At the recent observing session I've mentioned, my friends pointed out M13
to me, easy to observe through an eyepiece in one of their Dobs -- but close
to the zenith, and not so comfortable for my neck with 7X50 binoculars! I
decided to reserve closer binocular scrutiny of that object for another
session in order to be kinder and gentler to my neck muscles -- although
a lounge chair might have been just the ticket.
Most appreciatively,
Margo
|
| | | | | |
Date: 01 Jul 2007 23:35:52
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
|
John Nichols <bejay@worldnet.att.net > wrote:
> Adjustable observing chairs are an absolute must. CosmoComfort
> (www.cosmocomfort.com) makes a really good one. Among other things, both
> the seat and back are padded. You can get it for under $200 at Oceanside
> Pacific.
Thanks for this recommendation: looking at the information, I can see that
CosmoComfort does have a nice range of adjustable heights (10"-34", or about
25cm-86cm), and also padding on the back. I've read suggestions that for
colder weather, that padding might reduce body heat loss through contact
with metal supports -- maybe people could comment on this point.
Also, the weight is only about 16 pounds or 7.3kg -- less than either
the OTA or base of my 20cm f/6 Dob.
By the way, I've found that the folks at Oceanside are very friendly and
helpful.
Most appreciatively,
Margo
|
| | | | | | |
Date: 02 Jul 2007 02:17:34
From: John Nichols
Subject: Re: Advice on use of straight finder?
|
"Margo Schulter" <mschulter@web1.calweb.com > wrote in message
news:46883a58$0$31893$d368eab@news.calweb.com...
> John Nichols <bejay@worldnet.att.net> wrote:
>
>> Adjustable observing chairs are an absolute must. CosmoComfort
>> (www.cosmocomfort.com) makes a really good one. Among other things, both
>> the seat and back are padded. You can get it for under $200 at Oceanside
>> Pacific.
>
> Thanks for this recommendation: looking at the information, I can see that
> CosmoComfort does have a nice range of adjustable heights (10"-34", or
> about
> 25cm-86cm), and also padding on the back. I've read suggestions that for
> colder weather, that padding might reduce body heat loss through contact
> with metal supports -- maybe people could comment on this point.
>
> Also, the weight is only about 16 pounds or 7.3kg -- less than either
> the OTA or base of my 20cm f/6 Dob.
>
> By the way, I've found that the folks at Oceanside are very friendly and
> helpful.
>
You're welcome!
|
| | | | | | | |
Date: 01 Jul 2007 22:05:36
From: Marty
Subject: Re: Advice on use of straight finder?
|
This is one of those things where you're going to run into different
opinions, and they'll all be right, at least for somebody. I've read
that right angle finder scopes are the dumbest invention ever made, but
I really like mine. I'm too old and stiff to get under a straight
finder, so I point my scope at a "starter star" with a red dot finder,
and then star hop to the right point with my right angle finder scope
and the Uranometria 2000.
Others will call me a blithering idiot.
Marty
|
| | | | | | | | |
Date: 02 Jul 2007 10:06:25
From: John Nichols
Subject: Re: Advice on use of straight finder?
|
"Marty" <movac5@webtv.net > wrote in message
news:1560-46886B80-359@storefull-3331.bay.webtv.net...
> This is one of those things where you're going to run into different
> opinions, and they'll all be right, at least for somebody. I've read
> that right angle finder scopes are the dumbest invention ever made, but
> I really like mine. I'm too old and stiff to get under a straight
> finder, so I point my scope at a "starter star" with a red dot finder,
> and then star hop to the right point with my right angle finder scope
> and the Uranometria 2000.
> Others will call me a blithering idiot.
> Marty
>
Where would you like that blithering idiot delivered?
|
| | | | | | | | |
Date: 01 Jul 2007 20:26:01
From: katrinaxx
Subject: Re: Advice on use of straight finder?
|
Marty wrote:
> Others will call me a blithering idiot.
>
>
Nah.... I'll call ya a cab. :)
|
| | | | | | | | | |
Date: 01 Jul 2007 23:42:09
From: Marty
Subject: Re: Advice on use of straight finder?
|
>Nah.... I'll call ya a cab. :)
CATHY! :D
I've been called a lot worse. Even in here. :)
Marty
|
| |
Date: 28 Jun 2007 15:26:18
From: canopus56
Subject: Re: Advice on use of straight finder?
|
On Jun 27, 3:09 am, Margo Schulter <mschul...@web1.calweb.com > wrote:
<snip >
> (1) Might it be a good rule to avoid or minimize
> use of the finder at or very close to the zenith?
> An alternative might be to use as a kind of finder
> . . .
Largely a matter of personal preference, the first thing I do with any
scope is to remove the straight finder and install a right-angle
finder. They are available from many companies, including:
www.telescope.com (Orion)
www.telescopes.com (Telescopes.com)
The ease and comfort of quickly switching between the finder and
eyepiece while remaining seated makes a night's session much more
relaxed, IMHO. It reduces targeting time. For pointing, I use a
unity finder, such as red dot or Telrad.
> (2) Might a good adjustable observing chair help with
> finder ergonomics, as well as with other aspects
> of observing like being more relaxed and thus
> able better to concentrate on those elusive
> faint fuzzies?
Accessories will kill you in this hobby, but IMHO, the observing chair
is the first essential thing you should buy with or just after buying
your telescope. The ability to see details is a function of having an
open and relaxed mind. That means sitting in a relaxed pose. For a
DOB, it cannot be done without an observing chair. Otherwise, your
neck and back will stress out within 1/2 to 3/4 of an hour and you
will find your scope gathering dust in the closet instead of putting
it in the back seat of your car.
- Canopus56
|
| | |
Date: 01 Jul 2007 23:50:19
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
|
canopus56 <canopus56@yahoo.com > wrote:
> Accessories will kill you in this hobby, but IMHO, the observing chair
> is the first essential thing you should buy with or just after buying
> your telescope. The ability to see details is a function of having an
> open and relaxed mind. That means sitting in a relaxed pose. For a
> DOB, it cannot be done without an observing chair. Otherwise, your
> neck and back will stress out within 1/2 to 3/4 of an hour and you
> will find your scope gathering dust in the closet instead of putting
> it in the back seat of your car.
Hi, there, and what I'm plcturing is sitting back and looking at some spiral
galaxy for a duration in the area of what your remarks suggest, say 30-45 min,
trying to sketch out (figuratively and ideally on paper also) the finer and
more subtle details with different angles of averted vision, etc. Clearly a
good observing chair -- what I might call "user-transparent" in the sense
that it's comfortable enough that I don't have to be aware of it for the most
part -- is a valuable ally.
Most appreciatively,
Margo
|
| |
Date: 28 Jun 2007 03:54:47
From:
Subject: Re: Advice on use of straight finder?
|
On Jun 27, 5:09 am, Margo Schulter <mschul...@web1.calweb.com > wrote:
> Hello, everyone, and I'm seeking advice on the ergonomics of how
> to use a 9X50 straight finder with a minimum of neck strain. This
> finder, which looks quite nice, is on my new Sky-Watcher 20cm f/6
> Dobsonian, which I hope will be seeing its first light within the
> next week or so.
>
> While a friend very favorably impressed with the construction of
> the scope advised me that I might consider a right-angle finder
> or red dot finder (the Telrad looks like a good choice for the
> latter approach), making the most of the straight-through 9X50
> finder very much appeals to me. This finder seems, so to speak,
> a not too distant cousin to the 7X50 binoculars I use with
> Taki's 8.5 Magnitude Star Atlas, often in light-polluted urban
> conditions with a limiting magnitude around 3, for starhopping
> by asterisms not readily visible to the naked eye. At my age,
> maybe the smaller exit pupil of the 9X50 finder might help <grin>.
>
> Would people have advice as to minimizing strain with this type
> of finder? Here are some possible questions which occur to me as
> someone focusing mainly on deep-sky observing:
>
> (1) Might it be a good rule to avoid or minimize
> use of the finder at or very close to the zenith?
> An alternative might be to use as a kind of finder
> my widest-field EP, a 30mm "not-quite-Nagler" with
> a tad more than 2deg TFOV at 40X. Maybe some
> extra study of an atlas for areas of interest that
> are going to be near the zenith during a given
> observation could make this strategy more successful.
>
> (2) Might a good adjustable observing chair help with
> finder ergonomics, as well as with other aspects
> of observing like being more relaxed and thus
> able better to concentrate on those elusive
> faint fuzzies?
>
> Maybe people's experience might reveal other aspects of the
> question that haven't occurred to me; thank you in advance
> for any suggestions.
>
When looking at most parts of the sky, a straight-through finder
should suffice. The zenith can be more troublesome, but you really
shouldn't have to spend much time looking through the finder anyway.
If you use a right-angle finder you will probably get a reversed
image, unless the finder has an Amici roof prism or other, additional
optics.
What works for me is to use a somewhat larger finder that has a higher
mag and is equipped with a wide-field eyepiece. This lets me get the
scope pointed at a star field very quickly because I can easily see
the stars and asterisms shown on my chart and sometimes the target
object itself.
|
| |
Date: 28 Jun 2007 02:58:02
From:
Subject: Re: Advice on use of straight finder?
|
On Jun 27, 5:09 am, Margo Schulter <mschul...@web1.calweb.com > wrote:
> (1) Might it be a good rule to avoid or minimize
> use of the finder at or very close to the zenith?
> An alternative might be to use as a kind of finder
> my widest-field EP, a 30mm "not-quite-Nagler" with
> a tad more than 2deg TFOV at 40X.
It's very useful to be able to star-hop through your eyepiece as well
as through your finderscope. It *does* require excellent star charts
-- but sooner or later, you're going to need those anyway.
However, it seems silly to me to have to change your star-hopping
technique just because the scope is pointed high in the sky. Anyway,
useful as it is to be able to star-hop through the eyepiece, it's
*much* slower to star-hop with a 2-degree field than with a 5- or 6-
degree field of view.
Those 200mm f/6 Dobs do tend to put both the eyepiece and the finder
at a very awkward height -- to low to view comfortably while standing
but too high to view from a standard chair. I've never owned one, but
a tall adjustable-height chair seems like the obvious solution.
Unfortunately, they're necessarily pretty heavy and bulky.
|
| |
Date: 28 Jun 2007 02:49:33
From:
Subject: Re: Advice on use of straight finder?
|
On Jun 27, 12:35 pm, William Hamblen <wrhamb...@comcast.net > wrote:
> You can put longer legs on the base
> pretty easily.
True enough. Doing so without compromising the Dob's stability is a
whole 'nother matter. Keeping the Dob stable, vibration-free, *and*
equally portable is quite a trick!
On the whole, I find lowering the observer almost always superior to
raising the telescope.
But even in the best of circumstances, I find straight-through
finderscopes a pain in the neck -- literally. If I've got things
really comfortable for looking through the eyepiece, then it's always
at least a little uncomfortable to look through the finderscope, and
vice versa.
This is, no doubt, less of a problem on SCTs than on Newts, which have
a large range of eyepiece height depending how high above the horizon
they're pointed.
|
| | |
Date: 28 Jun 2007 10:26:37
From: Ernie Wright
Subject: Re: Advice on use of straight finder?
|
tony_flanders@yahoo.com wrote:
> On Jun 27, 12:35 pm, William Hamblen <wrhamb...@comcast.net> wrote:
>
>> You can put longer legs on the base pretty easily.
>
> True enough. Doing so without compromising the Dob's stability is a
> whole 'nother matter. Keeping the Dob stable, vibration-free, *and*
> equally portable is quite a trick!
>
> On the whole, I find lowering the observer almost always superior to
> raising the telescope.
On the other hand...
I built a box to put my 8-inch f/6 Dob on. It's about 15 inches high,
made of pressure-treated 2x4s and some lag bolts. It's not attached to
the base, so it's always optional and has no effect on portability. I
use it as the base of a side table on my deck when it's not under the
Dob.
For me, at six feet, it puts the eyepiece exactly at eye level at the
zenith, and it's much more comfortable at all angles. It doesn't appear
to have any adverse effect on stability or vibration.
The downside of a chair is that you're always fiddling with it, either
adjusting the height or having to move it every time you change azimuth.
- Ernie http://home.comcast.net/~erniew
|
| |
Date: 27 Jun 2007 11:35:59
From: William Hamblen
Subject: Re: Advice on use of straight finder?
|
On 27 Jun 2007 09:09:17 GMT, Margo Schulter
<mschulter@web1.calweb.com > wrote:
>Hello, everyone, and I'm seeking advice on the ergonomics of how
>to use a 9X50 straight finder with a minimum of neck strain.
My experience is that to use a straight through finder, you often have
to bend or squat and look up, which will just about maximize neck
strain. You have two strategies: either get the finder low enough so
you can see through it while sitting on a chair or stool or get the
finder high enough so you can see through it while standing straight.
Some dobs are tall enough for you to stand straight. For others you
will have to raise the base. You can put longer legs on the base
pretty easily.
Otherwise you can put in a right angle finder. One with an amici roof
prism will have a view that is correctly oriented and is easier to
use.
A Telrad will help you get in the right part of the sky regardless of
the type of magnifying finder you use.
A adjustable chair increases the comfort factor.
Bud
--
The night is just the shadow of the Earth.
|
| |
Date: 27 Jun 2007 11:26:54
From: Dennis Woos
Subject: Re: Advice on use of straight finder?
|
"Margo Schulter" <mschulter@web1.calweb.com > wrote in message
news:4682293d$0$20021$d368eab@news.calweb.com...
> Hello, everyone, and I'm seeking advice on the ergonomics of how
> to use a 9X50 straight finder with a minimum of neck strain. This
> finder, which looks quite nice, is on my new Sky-Watcher 20cm f/6
> Dobsonian, which I hope will be seeing its first light within the
> next week or so.
>
> While a friend very favorably impressed with the construction of
> the scope advised me that I might consider a right-angle finder
> or red dot finder (the Telrad looks like a good choice for the
> latter approach), making the most of the straight-through 9X50
> finder very much appeals to me. This finder seems, so to speak,
> a not too distant cousin to the 7X50 binoculars I use with
> Taki's 8.5 Magnitude Star Atlas, often in light-polluted urban
> conditions with a limiting magnitude around 3, for starhopping
> by asterisms not readily visible to the naked eye. At my age,
> maybe the smaller exit pupil of the 9X50 finder might help <grin>.
We (my sons and I) use only Rigel Quickfinders on our scopes, and consider a
low-power eyepiece the magnified finder. I like Quickfinders better than
Telrads, as they are lighter and stand up taller. We also use binos - 7x50
to 20x80 - as magnified finders, and point to targets with a green laser
whose beam we can see in the scopes. Our sky is pretty good/dark (pushing
mag. 6), and we can see a lot of stars in our Quickfinders. The binos work
better than a finder mounted on a scope, and help us to then find stuff
using the Quickfinder (either using the laser or just more accurately
pinning down the surrounding stars).
>
> Would people have advice as to minimizing strain with this type
> of finder? Here are some possible questions which occur to me as
> someone focusing mainly on deep-sky observing:
>
> (1) Might it be a good rule to avoid or minimize
> use of the finder at or very close to the zenith?
> An alternative might be to use as a kind of finder
> my widest-field EP, a 30mm "not-quite-Nagler" with
> a tad more than 2deg TFOV at 40X. Maybe some
> extra study of an atlas for areas of interest that
> are going to be near the zenith during a given
> observation could make this strategy more successful.
>
> (2) Might a good adjustable observing chair help with
> finder ergonomics, as well as with other aspects
> of observing like being more relaxed and thus
> able better to concentrate on those elusive
> faint fuzzies?
A good observing chair is really important for observing. It may also help
you to get your eye comfortably positioned behind the finder.
>
> Maybe people's experience might reveal other aspects of the
> question that haven't occurred to me; thank you in advance
> for any suggestions.
>
> Most appreciatively,
>
> Margo Schulter
> mschulter@calweb.com
>
>
|
| | |
Date: 02 Jul 2007 00:38:42
From: Margo Schulter
Subject: Re: Advice on use of straight finder?
|
Dennis Woos <dpwoos@gmavt.net > wrote:
> We (my sons and I) use only Rigel Quickfinders on our scopes, and consider a
> low-power eyepiece the magnified finder. I like Quickfinders better than
> Telrads, as they are lighter and stand up taller. We also use binos - 7x50
> to 20x80 - as magnified finders, and point to targets with a green laser
> whose beam we can see in the scopes. Our sky is pretty good/dark (pushing
> mag. 6), and we can see a lot of stars in our Quickfinders. The binos work
> better than a finder mounted on a scope, and help us to then find stuff
> using the Quickfinder (either using the laser or just more accurately
> pinning down the surrounding stars).
Hi, Dennis, and thanks for the information on the Rigel QuikFinder.
One question I might have is if you or others use QuikFinder charts similar
to the Telrad charts or overlays with the rings of the pattern helping to
position a brighter object so as to center on a fainter one. I took a look
at a manual for the QuikFinder available on the Web, and it described two
rings, one at 2 degrees and the other at 0.5 degrees.
On the green laser option, what happened at an observing session I've been
writing about is that when I found what looked like a nebulosity with
binoculars, one of my friends pointed a green laser and asked me to direct
him to the area -- whereupon they got a Dob on the area, and concluded that
it was an open cluster with nebulosity. From your comments, as well as that
first experience, I'd guess that this kind of teamwork can be fun and
effective.
Most appreciatively,
Margo
|
| | | |
Date: 02 Jul 2007 00:12:11
From: Dennis Woos
Subject: Re: Advice on use of straight finder?
|
"Margo Schulter" <mschulter@web1.calweb.com > wrote in message
news:46884912$0$30771$d368eab@news.calweb.com...
> Dennis Woos <dpwoos@gmavt.net> wrote:
>
>> We (my sons and I) use only Rigel Quickfinders on our scopes, and
>> consider a
>> low-power eyepiece the magnified finder. I like Quickfinders better than
>> Telrads, as they are lighter and stand up taller. We also use binos -
>> 7x50
>> to 20x80 - as magnified finders, and point to targets with a green laser
>> whose beam we can see in the scopes. Our sky is pretty good/dark (pushing
>> mag. 6), and we can see a lot of stars in our Quickfinders. The binos
>> work
>> better than a finder mounted on a scope, and help us to then find stuff
>> using the Quickfinder (either using the laser or just more accurately
>> pinning down the surrounding stars).
>
> Hi, Dennis, and thanks for the information on the Rigel QuikFinder.
>
> One question I might have is if you or others use QuikFinder charts
> similar
> to the Telrad charts or overlays with the rings of the pattern helping to
> position a brighter object so as to center on a fainter one. I took a look
> at a manual for the QuikFinder available on the Web, and it described two
> rings, one at 2 degrees and the other at 0.5 degrees.
I have used it to measure distance, though in this application I think the
Telrad has an advantage in that it has 3 rings, with the outer at 4 degrees.
However, I most often use it as a simple pointing device, as in fairly dark
skies there is usually one or more stars to point at/near/between. There are
exceptions, such as the Helix Nebula. In cases like this where (at least for
me) the neighborhood is sparse and lacking a good context, the binos/green
laser technique works very well. Another very important aspect to any 1x
pointer is that it be dimmable and optically clear. You need to be able to
see stars through it, and after you are dark adapted you need to turn down
the brightness to be very, very low.
>
> On the green laser option, what happened at an observing session I've been
> writing about is that when I found what looked like a nebulosity with
> binoculars, one of my friends pointed a green laser and asked me to direct
> him to the area -- whereupon they got a Dob on the area, and concluded
> that
> it was an open cluster with nebulosity. From your comments, as well as
> that
> first experience, I'd guess that this kind of teamwork can be fun and
> effective.
It is something my sons and I do regularly. From an early age I have asked
them to find stuff for us, while I either sit around or chat or check out
something else, etc. They enjoy this challenge, and it keeps their interest
while freezing/fighting mosquitos/etc. Once they have the target, either
there are some bright stars to point to and/or they illuminate it with the
green laser which we follow with the scope(s). An accessory which I will
someday make is a bracket to hold the laser, and a remote on/off switch so
that I can use this technique when observing alone. However, I rarely
observe alone so it has not been at the top of my list. In my mind the best
finder is binos on a nice mount, with the scope coupled to the binos via the
laser.
Finally, I would say that a good low-power wide-field eyepiece is as
important as a good 1x finder, and the binos/green laser. I would buy the
best I could afford, with attention to good performance at the outer
portions of the fov. Fortunately, there are more eyepieces in this category
than ever before, and they are becoming increasingly reasonable in price.
Dennis
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Date: 27 Jun 2007 11:25:57
From: RMOLLISE
Subject: Re: Advice on use of straight finder?
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On Jun 27, 4:09 am, Margo Schulter <mschul...@web1.calweb.com > wrote:
> Hello, everyone, and I'm seeking advice on the ergonomics of how
> to use a 9X50 straight finder with a minimum of neck strain. This
> finder, which looks quite nice, is on my new Sky-Watcher 20cm f/6
> Dobsonian, which I hope will be seeing its first light within the
> next week or so.
>
> While a friend very favorably impressed with the construction of
> the scope advised me that I might consider a right-angle finder
> or red dot finder (the Telrad looks like a good choice for the
> latter approach), making the most of the straight-through 9X50
> finder very much appeals to me. This finder seems, so to speak,
> a not too distant cousin to the 7X50 binoculars I use with
> Taki's 8.5 Magnitude Star Atlas, often in light-polluted urban
> conditions with a limiting magnitude around 3, for starhopping
> by asterisms not readily visible to the naked eye. At my age,
> maybe the smaller exit pupil of the 9X50 finder might help <grin>.
>
> Would people have advice as to minimizing strain with this type
> of finder? Here are some possible questions which occur to me as
> someone focusing mainly on deep-sky observing:
>
> (1) Might it be a good rule to avoid or minimize
> use of the finder at or very close to the zenith?
> An alternative might be to use as a kind of finder
> my widest-field EP, a 30mm "not-quite-Nagler" with
> a tad more than 2deg TFOV at 40X. Maybe some
> extra study of an atlas for areas of interest that
> are going to be near the zenith during a given
> observation could make this strategy more successful.
>
> (2) Might a good adjustable observing chair help with
> finder ergonomics, as well as with other aspects
> of observing like being more relaxed and thus
> able better to concentrate on those elusive
> faint fuzzies?
>
> Maybe people's experience might reveal other aspects of the
> question that haven't occurred to me; thank you in advance
> for any suggestions.
>
> Most appreciatively,
>
> Margo Schulter
> mschul...@calweb.com
Hi:
I suspect with a little practice you'll find the straight through
finder is not as much of a problem to use as you think. A right-angle-
correct-image finder is an option, but I find these actually _more_
awkward to use.
Unk Rod
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